The invention relates to a radio system and a method of establishing a connection between network elements in a radio system comprising as network elements one or more base stations, a base station controller and a network management system that are operatively interconnected by means of telecommunication connections.
Modern radio networks are highly complicated systems comprising several different network components, such as base stations, base station controllers, mobile services switching centres, different transmission networks and cross-connection devices. When networks extend or capacity need increases, to build radio networks and to extend existing networks is a demanding and complex procedure that requires a great deal of planning, time and work. FIG. 1 illustrates an example of a radio system comprising a base station controller 100, cross-connection equipment 102, three base stations 104 to 108 and a network management unit 110. The base station 100 is connected by telecommunication connections 112 to the cross-connection equipment 102 to which, in turn, the base station 104 is directly connected, and to which the base stations 106 to 108 are coupled in series such that information supplied from the base station controller to the base station 108 is transmitted via the base station 106. By means of existing methods, each element is to be manually configured in situ one node at a time according to precalculated parameters and schemes. The management connection has thus to be established manually.
Typically, in digital systems information between the network elements is transmitted in frames comprising a plurality of time slots. For example in the digital GSM system a connection between a base station and a base station controller is called Abis interface. Typically, the connection is of a frame form and comprises 32 time slots transmitting traffic at a 64 kbit/s transmission rate, the total capacity thus being 2 Mbit/s. FIG. 2 illustrates an Abis interface. Each connection between a base station and a base station controller takes up some time slots from said frame. The number of time slots per a base station varies depending on the size of the base station and the traffic channel capacity.
When network elements, either cross-connection equipment or base stations, are to be added to an existing system, for example similar to the system according to FIG. 1, known remote control methods are no longer feasible. When the equipment is physically installed and connected either to an existing or built telecommunication connection with the system, the telecommunication connections between a base station and a base station controller must in detail be designed and configured at gate, time slot and partial time slot levels. As far as a network element to be installed is concerned, settings must be fixed by installation personnel in order to enable a management connection to the base station controller to be established, whereupon settings for a new base station can also be fixed from the management unit either manually or by software. Hence, to add a new element is a time-consuming and demanding procedure also susceptible to errors. In order to test a new base station and telecommunication connections allocated thereto, the base station installation personnel must communicate with the network management personnel. This requires detailed task coordination between the management unit personnel and the installation personnel so as to avoid unnecessary waiting times.
An object of the invention is thus to provide a method and a system implementing the method so as to enable the above-mentioned problems to be solved. This is achieved by a method of establishing a connection between network elements in a radio system comprising as network elements one or more base stations, a base station controller and a network management system that are operatively interconnected by means of telecommunication connections comprising traffic channels and control channels, and in which system information between the network elements is transmitted in frames that are divided into time slots, and in which system the base station controller controls one or more base stations, and network element identification information has been fed into the network element to be installed, and in which method the network element is physically connected to the system by means of the telecommunication connections.
The method of the invention is characterized by predetermining identification information on base stations allowed to be connected to the base station controller for the base station controller, and the base station controller transmitting a communication channel at least in some of the frames the base station controller uses for communication with the network elements if the base station controller detects that it has been provided with identification information on base stations not yet connected to the base station controller, and after being physically installed, the network element to be installed searching the frames received by means of the telecommunication connections for communication control channels, and establishing a connection to the base station controller by means of the communication channels found.
The invention further relates to a radio system comprising one or more network elements, a base station controller and a network management system that are operatively interconnected by means of telecommunication connections comprising traffic channels and control channels, and in which system information between the network elements is transmitted in frames that are divided into time slots, and in which system the base station controller controls one or more network elements that comprise network element identification information.
The system of the invention is characterized by the base station controller being arranged to update the identification information on base stations allowed to be connected to the base station, and the base station controller being arranged to detect that that it has been provided with identification information on base stations not yet connected to the base station controller, and the base station controller being arranged to transmit a communication channel at least in some of the frames the base station controller uses for communication with the network elements, and the network element to be installed, after being physically installed, being arranged to search the frames received by means of the telecommunication connections for communication control channels, and to establish a connection to the base station controller by means of the communication channels found.
The preferred embodiments of the invention are disclosed in the dependent claims.
The invention is based on the idea that a base station controller controls and monitors the network element installation. Necessary telecommunication capacity is automatically allocated for the use of the network elements without manual couplings or adjustments. A network element to be installed and the base station controller communicate with each other by means of a communication control channel, and the necessary telecommunication capacity for the use of the network element is allocated from a group formed by free channels. Preferably, the aim is to minimize the proportion of separate time slots remaining in the group, in other words the aim is to obtain unbroken groups.
The method and system of the invention provide several advantages. Network element installation into a system is automatized. The amount of necessary manual work decreases significantly. Furthermore, time slot design of telecommunication connections between base station controllers and network elements becomes redundant since connections are automatically established, controlled by the base station controller. Automation enables potential errors, and, consequently, costs to be reduced. Further, the invention enables faster installations since installation personnel must no longer be simultaneously present in network control or in connection with base station controllers. Automation shortens installation time.
Network element installation requires no special and expensive training since automation also reduces the amount of necessary work on the installation site. After identification information on the network elements to be connected has been fed to the base station controller, it starts transmitting a communication control channel for establishing network element connections. When, after the physical installation, a network element is switched on, the network element initiates automatic installation by searching the frames received by means of telecommunication connections for communication control channels of the groups. After the connections and the appropriate base station controller are found, and the necessary channels having automatically been allocated for the use of the network element, the system can automatically test the connections and inform the installer that the connections are working, in other words that the network element is ready for the operational state.